Conventionally, as frame structures to be applied to the building body for forming a large indoor space such as large tents and tents warehouses, the morphological stability, high rigidity and strength are required. Thus, truss structures are mainly used.
On the other hand, with respect to a simple frame for constructing a relatively small indoor space such as a domestic garage or an agricultural vinyl house, the roof is low in its own weight and relatively low in height. Therefore, it is possible to employ Rigit Frame (Rahmen Structure) to both side wall portions, while using the frame structure of the truss structure to the roof portion. According to another frame, a large number of tubes bent into an arch shape or an inverted U shape are supported by the legs in a standing manner. Meanwhile, a horizontal bar crossed at an intermediate position of each tube constitutes a rigid structure.
According to simple frame for constituting the small interior space of the prior art, both side wall portions are erected by rigid frame structure. Accordingly, it is weak against an external force such as wind pressure, and inferior in vibration resistance. It is necessary to apply reinforcement measures as necessary. Also, as the distance between the frame members and the bending tubes arranged at regular intervals increases, the curtain that is stretched or the thin plate material that is attached tends to be deflected. Therefore, when its deflection increases due to secular change, it is unsightly appearance.
Meanwhile, the applicant has developed and improved for the push-through bending method and the processing unit of the tube or bar since 1989. Currently, bending machining against tube material is possible stably and in high-precision with small radius of curvature while preventing a tube section from being flattened. Further, it is possible to realize the bending continuous further freely three-dimensionally.
Therefore, it is an object of the present invention to provide a frame structure using a tube subjected to bending processing by the above pushing bending apparatus, thereby solving the problem of a simple body constituting the small-sized interior space.
With respect to bars, the processing efficiency and the processing accuracy cannot be obtained compared to the tubes even by using the pushing bending apparatus. Thus, the conventional press bending processing is used. However, since it can be used for the frame structure described below, it does not exclude bars.